[libclang] Introduce clang_getFileUniqueID which returns a struct

for a CXFile containing device/inode/modification time.

Intended to be useful as a key associated with a unique file across
an indexing session.

rdar://13091837

llvm-svn: 173559

clang/include/clang-c/Index.h

@@ -32,7 +32,7 @@
  * compatible, thus CINDEX_VERSION_MAJOR is expected to remain stable.
  */
 #define CINDEX_VERSION_MAJOR 0
-#define CINDEX_VERSION_MINOR 10
+#define CINDEX_VERSION_MINOR 11
 
 #define CINDEX_VERSION_ENCODE(major, minor) ( \
       ((major) * 10000)                       \
@@ -296,6 +296,24 @@ CINDEX_LINKAGE CXString clang_getFileName(CXFile SFile);
  */
 CINDEX_LINKAGE time_t clang_getFileTime(CXFile SFile);
 
+/**
+ * \brief Uniquely identifies a CXFile, that refers to the same underlying file,
+ * across an indexing session.
+ */
+typedef struct {
+  unsigned long long data[3];
+} CXFileUniqueID;
+
+/**
+ * \brief Retrieve the unique ID for the given \c file.
+ *
+ * \param file the file to get the ID for.
+ * \param outID stores the returned CXFileUniqueID.
+ * \returns If there was a failure getting the unique ID, returns non-zero,
+ * otherwise returns 0.
+*/
+CINDEX_LINKAGE int clang_getFileUniqueID(CXFile file, CXFileUniqueID *outID);
+
 /**
  * \brief Determine whether the given header is guarded against
  * multiple inclusions, either with the conventional

clang/tools/libclang/CIndex.cpp

@@ -2960,6 +2960,21 @@ unsigned clang_isFileMultipleIncludeGuarded(CXTranslationUnit tu, CXFile file) {
                                           .isFileMultipleIncludeGuarded(FEnt);
 }
 
+int clang_getFileUniqueID(CXFile file, CXFileUniqueID *outID) {
+  if (!file || !outID)
+    return 1;
+
+#ifdef LLVM_ON_WIN32
+  return 1; // inodes not supported on windows.
+#else
+  FileEntry *FEnt = static_cast<FileEntry *>(file);
+  outID->data[0] = FEnt->getDevice();
+  outID->data[1] = FEnt->getInode();
+  outID->data[2] = FEnt->getModificationTime();
+  return 0;
+#endif
+}
+
 } // end: extern "C"
 
 //===----------------------------------------------------------------------===//

clang/tools/libclang/libclang.exports

@@ -166,6 +166,7 @@ clang_getFile
 clang_getFileLocation
 clang_getFileName
 clang_getFileTime
+clang_getFileUniqueID
 clang_getFunctionTypeCallingConv
 clang_getIBOutletCollectionType
 clang_getIncludedFile